A fuel cell is a device that directly converts chemical energy stored in hydrocarbon fuel into electrical energy by means of an electrochemical reaction. Generally, a fuel cell comprises an anode and a cathode separated by an electrolyte, which serves to conduct electrically charged ions. In order to produce a useful power level, a number of individual fuel cells are stacked in series with an electrically conductive separator plate between each pair of the cells. The design of the supporting structure of the fuel cells and materials used for the electrolyte determine the type and performance of the fuel cell system.
A molten carbonate fuel cell (MCFC) operates by passing a reactant fuel gas through the anode, while oxidizing gas is passed through the cathode. A typical MCFC includes a porous nickel (Ni) anode that has been stabilized with metal alloy additives, and a porous, in situ oxidized nickel (Ni) or nickel oxide (NiO) cathode, separated from the anode by a porous matrix with alkali electrolyte. MCFCs operate on fuel and oxidant gas, typically at temperatures of about 650° C.
The operating life and performance of the MCFCs depends in part on the characteristics of the anode and cathode employed in the fuel cell. Although higher operating temperatures of MCFCs enable higher overall fuel cell system efficiency and greater flexibility in the use of available fuels, higher temperatures also place severe demands on corrosion stability and life of fuel cell components. For example, MCFC cathodes need to have excellent conductivity, high mechanical strength and durability, and low dissolution rate.
During manufacturing of MCFC cathodes, a Ni cathode electrode is typically sintered and impregnated with electrolyte at temperatures above 500° C. Microwave heating and electric- or gas-fired furnaces have been used for heating the work piece so as to achieve these temperatures and to melt the electrolyte. However, microwave heating, a gas furnace, or an electric furnace are not well suited for rapidly heating large work pieces or for ensuring a uniform temperature distribution within the work piece, which reduces the quality of the resulting work piece. Further, usage of the microwave heating and gas or electric furnaces results in significant operating costs caused by the use of electricity or gas, a large floor space required due to the size of the equipment, and equipment maintenance costs.